The present invention relates to a method of and an apparatus for automatically reading a band arrayal pattern, and more particularly to a band arrayal pattern-automatic reading method and apparatus which are well suited to read the base band arrayal pattern of a gene imaged on an X-ray film and to correctly detect the band arrayal order of base codes.
It has been made clear and is generally known that the gene of a living organism is composed of the substance deoxyribonucleic acid (DNA) and has a structure in which the four kinds of organic bases; adenine (A), cytosine (C), guanine (G) and thymine (T) are arrayed in a double-helical shape. A method of determining the base arrayal of the DNA is the shotgun method. With this method, the chain of the DNA is broken up by reagents for chemically cutting the respective bases, and the individual bases are arrayed in accordance with their different lengths by electrophoresis, whereupon they are imaged on a film with X-rays. The X-ray film obtained after the electrophoresis bears belt-like patterns expressive of the arrayal of the four kinds of bases. As shown in FIG. 2A, on the film 3 subjected to the X-ray imaging, a plurality of bands 4 extending substantially perpendicularly to a lane are arrayed within the lane which is the valid range of each of the base codes A, C, G and T. The gene can be analyzed by analyzing the base arrayal on this film.
For the purpose of the analysis, the base arrayal pattern on the film is input to a computer. As an input device therefor, there has heretofore been one employing a digitizer in which the X-ray film 3 is placed on the digitizer, and the positions of the bands 4 on the film 3 are successively pointed to with a pen or cursor so as to input the output signals of the digitizer to the computer.
With the prior-art device, since the bands on the X-ray film are input by successively pointing to them by means of the pen or the like, it expends labor to input all the bands on the X-ray film. When the input operation is conducted for a long time, input mistakes increase.
Besides, a method of determining the base arrayal of the DNA has been disclosed in the official gazette of Japanese Patent Application Laid-open No. 59-126247, in which band positions are automatically read with a laser, and with reference to respective separation development positions having appeared in the separation development series of a mixture, the separation development positions of scission decomposition products unique to bases having appeared in another separation development series are compared for identification.
Another prior-art method of determining the base arrayal of the DNA has been disclosed in the official gazette of Japanese Patent Application Laid-open No. 59-44648, in which controls are put on both the sides of a sample so as to judge whether or not a band exists.
These prior art methods involve various restrictions in practical use.